commit 372a03e01853f860560eade508794dd274e9b390 upstream. Ext4 needs to serialize unaligned direct AIO because the zeroing of partial blocks of two competing unaligned AIOs can result in data corruption. However it decides not to serialize if the potentially unaligned aio is past i_size with the rationale that no pending writes are possible past i_size. Unfortunately if the i_size is not block aligned and the second unaligned write lands past i_size, but still into the same block, it has the potential of corrupting the previous unaligned write to the same block. This is (very simplified) reproducer from Frank // 41472 = (10 * 4096) + 512 // 37376 = 41472 - 4096 ftruncate(fd, 41472); io_prep_pwrite(iocbs[0], fd, buf[0], 4096, 37376); io_prep_pwrite(iocbs[1], fd, buf[1], 4096, 41472); io_submit(io_ctx, 1, &iocbs[1]); io_submit(io_ctx, 1, &iocbs[2]); io_getevents(io_ctx, 2, 2, events, NULL); Without this patch the 512B range from 40960 up to the start of the second unaligned write (41472) is going to be zeroed overwriting the data written by the first write. This is a data corruption. 00000000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 * 00009200 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 * 0000a000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 * 0000a200 31 31 31 31 31 31 31 31 31 31 31 31 31 31 31 31 With this patch the data corruption is avoided because we will recognize the unaligned_aio and wait for the unwritten extent conversion. 00000000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 * 00009200 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 * 0000a200 31 31 31 31 31 31 31 31 31 31 31 31 31 31 31 31 * 0000b200 Reported-by: Frank Sorenson <fsorenso@redhat.com> Signed-off-by: Lukas Czerner <lczerner@redhat.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Fixes: e9e3bcecf44c ("ext4: serialize unaligned asynchronous DIO") Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
798 lines
20 KiB
C
798 lines
20 KiB
C
/*
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* linux/fs/ext4/file.c
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*
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* Copyright (C) 1992, 1993, 1994, 1995
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* Remy Card (card@masi.ibp.fr)
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* Laboratoire MASI - Institut Blaise Pascal
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* Universite Pierre et Marie Curie (Paris VI)
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*
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* from
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*
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* linux/fs/minix/file.c
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*
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* Copyright (C) 1991, 1992 Linus Torvalds
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*
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* ext4 fs regular file handling primitives
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*
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* 64-bit file support on 64-bit platforms by Jakub Jelinek
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* (jj@sunsite.ms.mff.cuni.cz)
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*/
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#include <linux/time.h>
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#include <linux/fs.h>
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#include <linux/mount.h>
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#include <linux/path.h>
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#include <linux/dax.h>
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#include <linux/quotaops.h>
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#include <linux/pagevec.h>
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#include <linux/uio.h>
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#include "ext4.h"
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#include "ext4_jbd2.h"
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#include "xattr.h"
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#include "acl.h"
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#ifdef CONFIG_EXT4CRYPT_SDP
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#include "sdp/fscrypto_sdp_cache.h"
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#endif
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/*
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* Called when an inode is released. Note that this is different
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* from ext4_file_open: open gets called at every open, but release
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* gets called only when /all/ the files are closed.
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*/
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static int ext4_release_file(struct inode *inode, struct file *filp)
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{
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if (ext4_test_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE)) {
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ext4_alloc_da_blocks(inode);
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ext4_clear_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE);
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}
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/* if we are the last writer on the inode, drop the block reservation */
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if ((filp->f_mode & FMODE_WRITE) &&
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(atomic_read(&inode->i_writecount) == 1) &&
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!EXT4_I(inode)->i_reserved_data_blocks)
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{
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down_write(&EXT4_I(inode)->i_data_sem);
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ext4_discard_preallocations(inode);
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up_write(&EXT4_I(inode)->i_data_sem);
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}
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if (is_dx(inode) && filp->private_data)
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ext4_htree_free_dir_info(filp->private_data);
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return 0;
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}
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static void ext4_unwritten_wait(struct inode *inode)
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{
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wait_queue_head_t *wq = ext4_ioend_wq(inode);
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wait_event(*wq, (atomic_read(&EXT4_I(inode)->i_unwritten) == 0));
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}
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/*
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* This tests whether the IO in question is block-aligned or not.
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* Ext4 utilizes unwritten extents when hole-filling during direct IO, and they
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* are converted to written only after the IO is complete. Until they are
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* mapped, these blocks appear as holes, so dio_zero_block() will assume that
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* it needs to zero out portions of the start and/or end block. If 2 AIO
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* threads are at work on the same unwritten block, they must be synchronized
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* or one thread will zero the other's data, causing corruption.
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*/
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static int
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ext4_unaligned_aio(struct inode *inode, struct iov_iter *from, loff_t pos)
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{
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struct super_block *sb = inode->i_sb;
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int blockmask = sb->s_blocksize - 1;
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if (pos >= ALIGN(i_size_read(inode), sb->s_blocksize))
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return 0;
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if ((pos | iov_iter_alignment(from)) & blockmask)
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return 1;
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return 0;
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}
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static ssize_t
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ext4_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
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{
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struct file *file = iocb->ki_filp;
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struct inode *inode = file_inode(iocb->ki_filp);
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struct mutex *aio_mutex = NULL;
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struct blk_plug plug;
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int o_direct = iocb->ki_flags & IOCB_DIRECT;
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int overwrite = 0;
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ssize_t ret;
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/*
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* Unaligned direct AIO must be serialized; see comment above
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* In the case of O_APPEND, assume that we must always serialize
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*/
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if (o_direct &&
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ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS) &&
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!is_sync_kiocb(iocb) &&
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(iocb->ki_flags & IOCB_APPEND ||
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ext4_unaligned_aio(inode, from, iocb->ki_pos))) {
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aio_mutex = ext4_aio_mutex(inode);
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mutex_lock(aio_mutex);
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ext4_unwritten_wait(inode);
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}
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mutex_lock(&inode->i_mutex);
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ret = generic_write_checks(iocb, from);
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if (ret <= 0)
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goto out;
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/*
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* If we have encountered a bitmap-format file, the size limit
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* is smaller than s_maxbytes, which is for extent-mapped files.
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*/
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if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
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struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
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if (iocb->ki_pos >= sbi->s_bitmap_maxbytes) {
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ret = -EFBIG;
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goto out;
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}
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iov_iter_truncate(from, sbi->s_bitmap_maxbytes - iocb->ki_pos);
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}
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iocb->private = &overwrite;
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if (o_direct) {
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size_t length = iov_iter_count(from);
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loff_t pos = iocb->ki_pos;
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blk_start_plug(&plug);
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/* check whether we do a DIO overwrite or not */
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if (ext4_should_dioread_nolock(inode) && !aio_mutex &&
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!file->f_mapping->nrpages && pos + length <= i_size_read(inode)) {
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struct ext4_map_blocks map;
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unsigned int blkbits = inode->i_blkbits;
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int err, len;
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map.m_lblk = pos >> blkbits;
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map.m_len = (EXT4_BLOCK_ALIGN(pos + length, blkbits) >> blkbits)
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- map.m_lblk;
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len = map.m_len;
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err = ext4_map_blocks(NULL, inode, &map, 0);
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/*
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* 'err==len' means that all of blocks has
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* been preallocated no matter they are
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* initialized or not. For excluding
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* unwritten extents, we need to check
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* m_flags. There are two conditions that
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* indicate for initialized extents. 1) If we
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* hit extent cache, EXT4_MAP_MAPPED flag is
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* returned; 2) If we do a real lookup,
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* non-flags are returned. So we should check
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* these two conditions.
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*/
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if (err == len && (map.m_flags & EXT4_MAP_MAPPED))
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overwrite = 1;
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}
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}
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#ifdef CONFIG_EXT4CRYPT_SDP
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if (fscrypt_sdp_file_not_writable(file))
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ret = -EINVAL;
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else
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ret = __generic_file_write_iter(iocb, from);
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#else
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ret = __generic_file_write_iter(iocb, from);
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#endif
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mutex_unlock(&inode->i_mutex);
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if (ret > 0) {
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ssize_t err;
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err = generic_write_sync(file, iocb->ki_pos - ret, ret);
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if (err < 0)
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ret = err;
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}
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if (o_direct)
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blk_finish_plug(&plug);
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if (aio_mutex)
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mutex_unlock(aio_mutex);
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return ret;
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out:
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mutex_unlock(&inode->i_mutex);
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if (aio_mutex)
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mutex_unlock(aio_mutex);
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return ret;
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}
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#ifdef CONFIG_FS_DAX
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static void ext4_end_io_unwritten(struct buffer_head *bh, int uptodate)
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{
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struct inode *inode = bh->b_assoc_map->host;
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/* XXX: breaks on 32-bit > 16TB. Is that even supported? */
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loff_t offset = (loff_t)(uintptr_t)bh->b_private << inode->i_blkbits;
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int err;
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if (!uptodate)
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return;
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WARN_ON(!buffer_unwritten(bh));
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err = ext4_convert_unwritten_extents(NULL, inode, offset, bh->b_size);
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}
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static int ext4_dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
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{
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int result;
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handle_t *handle = NULL;
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struct inode *inode = file_inode(vma->vm_file);
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struct super_block *sb = inode->i_sb;
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bool write = vmf->flags & FAULT_FLAG_WRITE;
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if (write) {
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sb_start_pagefault(sb);
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file_update_time(vma->vm_file);
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down_read(&EXT4_I(inode)->i_mmap_sem);
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handle = ext4_journal_start_sb(sb, EXT4_HT_WRITE_PAGE,
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EXT4_DATA_TRANS_BLOCKS(sb));
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} else
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down_read(&EXT4_I(inode)->i_mmap_sem);
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if (IS_ERR(handle))
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result = VM_FAULT_SIGBUS;
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else
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result = __dax_fault(vma, vmf, ext4_get_block_dax,
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ext4_end_io_unwritten);
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if (write) {
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if (!IS_ERR(handle))
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ext4_journal_stop(handle);
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up_read(&EXT4_I(inode)->i_mmap_sem);
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sb_end_pagefault(sb);
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} else
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up_read(&EXT4_I(inode)->i_mmap_sem);
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return result;
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}
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static int ext4_dax_pmd_fault(struct vm_area_struct *vma, unsigned long addr,
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pmd_t *pmd, unsigned int flags)
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{
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int result;
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handle_t *handle = NULL;
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struct inode *inode = file_inode(vma->vm_file);
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struct super_block *sb = inode->i_sb;
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bool write = flags & FAULT_FLAG_WRITE;
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if (write) {
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sb_start_pagefault(sb);
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file_update_time(vma->vm_file);
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down_read(&EXT4_I(inode)->i_mmap_sem);
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handle = ext4_journal_start_sb(sb, EXT4_HT_WRITE_PAGE,
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ext4_chunk_trans_blocks(inode,
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PMD_SIZE / PAGE_SIZE));
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} else
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down_read(&EXT4_I(inode)->i_mmap_sem);
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if (IS_ERR(handle))
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result = VM_FAULT_SIGBUS;
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else
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result = __dax_pmd_fault(vma, addr, pmd, flags,
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ext4_get_block_dax, ext4_end_io_unwritten);
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if (write) {
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if (!IS_ERR(handle))
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ext4_journal_stop(handle);
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up_read(&EXT4_I(inode)->i_mmap_sem);
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sb_end_pagefault(sb);
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} else
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up_read(&EXT4_I(inode)->i_mmap_sem);
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return result;
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}
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static int ext4_dax_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
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{
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int err;
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struct inode *inode = file_inode(vma->vm_file);
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sb_start_pagefault(inode->i_sb);
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file_update_time(vma->vm_file);
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down_read(&EXT4_I(inode)->i_mmap_sem);
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err = __dax_mkwrite(vma, vmf, ext4_get_block_dax,
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ext4_end_io_unwritten);
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up_read(&EXT4_I(inode)->i_mmap_sem);
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sb_end_pagefault(inode->i_sb);
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return err;
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}
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/*
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* Handle write fault for VM_MIXEDMAP mappings. Similarly to ext4_dax_mkwrite()
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* handler we check for races agaist truncate. Note that since we cycle through
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* i_mmap_sem, we are sure that also any hole punching that began before we
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* were called is finished by now and so if it included part of the file we
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* are working on, our pte will get unmapped and the check for pte_same() in
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* wp_pfn_shared() fails. Thus fault gets retried and things work out as
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* desired.
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*/
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static int ext4_dax_pfn_mkwrite(struct vm_area_struct *vma,
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struct vm_fault *vmf)
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{
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struct inode *inode = file_inode(vma->vm_file);
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struct super_block *sb = inode->i_sb;
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int ret = VM_FAULT_NOPAGE;
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loff_t size;
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sb_start_pagefault(sb);
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file_update_time(vma->vm_file);
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down_read(&EXT4_I(inode)->i_mmap_sem);
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size = (i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT;
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if (vmf->pgoff >= size)
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ret = VM_FAULT_SIGBUS;
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up_read(&EXT4_I(inode)->i_mmap_sem);
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sb_end_pagefault(sb);
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return ret;
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}
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static const struct vm_operations_struct ext4_dax_vm_ops = {
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.fault = ext4_dax_fault,
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.pmd_fault = ext4_dax_pmd_fault,
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.page_mkwrite = ext4_dax_mkwrite,
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.pfn_mkwrite = ext4_dax_pfn_mkwrite,
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};
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#else
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#define ext4_dax_vm_ops ext4_file_vm_ops
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#endif
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static const struct vm_operations_struct ext4_file_vm_ops = {
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.fault = ext4_filemap_fault,
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.map_pages = filemap_map_pages,
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.page_mkwrite = ext4_page_mkwrite,
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};
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static int ext4_file_mmap(struct file *file, struct vm_area_struct *vma)
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{
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struct inode *inode = file->f_mapping->host;
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if (ext4_encrypted_inode(inode)) {
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int err = ext4_get_encryption_info(inode);
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if (err)
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return 0;
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if (ext4_encryption_info(inode) == NULL)
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return -ENOKEY;
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}
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file_accessed(file);
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if (IS_DAX(file_inode(file))) {
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vma->vm_ops = &ext4_dax_vm_ops;
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vma->vm_flags |= VM_MIXEDMAP | VM_HUGEPAGE;
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} else {
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vma->vm_ops = &ext4_file_vm_ops;
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}
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return 0;
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}
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static int ext4_file_open(struct inode * inode, struct file * filp)
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{
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struct super_block *sb = inode->i_sb;
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struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
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struct vfsmount *mnt = filp->f_path.mnt;
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struct dentry *dir;
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struct path path;
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char buf[64], *cp;
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int ret;
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if (unlikely(!(sbi->s_mount_flags & EXT4_MF_MNTDIR_SAMPLED) &&
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!(sb->s_flags & MS_RDONLY))) {
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sbi->s_mount_flags |= EXT4_MF_MNTDIR_SAMPLED;
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/*
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* Sample where the filesystem has been mounted and
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* store it in the superblock for sysadmin convenience
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* when trying to sort through large numbers of block
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* devices or filesystem images.
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*/
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memset(buf, 0, sizeof(buf));
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path.mnt = mnt;
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path.dentry = mnt->mnt_root;
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cp = d_path(&path, buf, sizeof(buf));
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if (!IS_ERR(cp)) {
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handle_t *handle;
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int err;
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handle = ext4_journal_start_sb(sb, EXT4_HT_MISC, 1);
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if (IS_ERR(handle))
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return PTR_ERR(handle);
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BUFFER_TRACE(sbi->s_sbh, "get_write_access");
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err = ext4_journal_get_write_access(handle, sbi->s_sbh);
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if (err) {
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ext4_journal_stop(handle);
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return err;
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}
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strlcpy(sbi->s_es->s_last_mounted, cp,
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sizeof(sbi->s_es->s_last_mounted));
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ext4_handle_dirty_super(handle, sb);
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ext4_journal_stop(handle);
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}
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}
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if (ext4_encrypted_inode(inode)) {
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ret = ext4_get_encryption_info(inode);
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if (ret) {
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printk(KERN_ERR "%s: failed to get encryption info (%d)", __func__, ret);
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return -EACCES;
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}
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if (ext4_encryption_info(inode) == NULL)
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return -ENOKEY;
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}
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dir = dget_parent(filp->f_path.dentry);
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if (ext4_encrypted_inode(d_inode(dir)) &&
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!ext4_is_child_context_consistent_with_parent(d_inode(dir), inode)) {
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ext4_warning(inode->i_sb,
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"Inconsistent encryption contexts: %lu/%lu\n",
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(unsigned long) d_inode(dir)->i_ino,
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(unsigned long) inode->i_ino);
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dput(dir);
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return -EPERM;
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}
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dput(dir);
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/*
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* Set up the jbd2_inode if we are opening the inode for
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* writing and the journal is present
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*/
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if (filp->f_mode & FMODE_WRITE) {
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ret = ext4_inode_attach_jinode(inode);
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if (ret < 0)
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|
return ret;
|
|
}
|
|
return dquot_file_open(inode, filp);
|
|
}
|
|
|
|
/*
|
|
* Here we use ext4_map_blocks() to get a block mapping for a extent-based
|
|
* file rather than ext4_ext_walk_space() because we can introduce
|
|
* SEEK_DATA/SEEK_HOLE for block-mapped and extent-mapped file at the same
|
|
* function. When extent status tree has been fully implemented, it will
|
|
* track all extent status for a file and we can directly use it to
|
|
* retrieve the offset for SEEK_DATA/SEEK_HOLE.
|
|
*/
|
|
|
|
/*
|
|
* When we retrieve the offset for SEEK_DATA/SEEK_HOLE, we would need to
|
|
* lookup page cache to check whether or not there has some data between
|
|
* [startoff, endoff] because, if this range contains an unwritten extent,
|
|
* we determine this extent as a data or a hole according to whether the
|
|
* page cache has data or not.
|
|
*/
|
|
static int ext4_find_unwritten_pgoff(struct inode *inode,
|
|
int whence,
|
|
struct ext4_map_blocks *map,
|
|
loff_t *offset)
|
|
{
|
|
struct pagevec pvec;
|
|
unsigned int blkbits;
|
|
pgoff_t index;
|
|
pgoff_t end;
|
|
loff_t endoff;
|
|
loff_t startoff;
|
|
loff_t lastoff;
|
|
int found = 0;
|
|
|
|
blkbits = inode->i_sb->s_blocksize_bits;
|
|
startoff = *offset;
|
|
lastoff = startoff;
|
|
endoff = (loff_t)(map->m_lblk + map->m_len) << blkbits;
|
|
|
|
index = startoff >> PAGE_CACHE_SHIFT;
|
|
end = endoff >> PAGE_CACHE_SHIFT;
|
|
|
|
pagevec_init(&pvec, 0);
|
|
do {
|
|
int i, num;
|
|
unsigned long nr_pages;
|
|
|
|
num = min_t(pgoff_t, end - index, PAGEVEC_SIZE - 1) + 1;
|
|
nr_pages = pagevec_lookup(&pvec, inode->i_mapping, index,
|
|
(pgoff_t)num);
|
|
if (nr_pages == 0)
|
|
break;
|
|
|
|
for (i = 0; i < nr_pages; i++) {
|
|
struct page *page = pvec.pages[i];
|
|
struct buffer_head *bh, *head;
|
|
|
|
/*
|
|
* If current offset is smaller than the page offset,
|
|
* there is a hole at this offset.
|
|
*/
|
|
if (whence == SEEK_HOLE && lastoff < endoff &&
|
|
lastoff < page_offset(pvec.pages[i])) {
|
|
found = 1;
|
|
*offset = lastoff;
|
|
goto out;
|
|
}
|
|
|
|
if (page->index > end)
|
|
goto out;
|
|
|
|
lock_page(page);
|
|
|
|
if (unlikely(page->mapping != inode->i_mapping)) {
|
|
unlock_page(page);
|
|
continue;
|
|
}
|
|
|
|
if (!page_has_buffers(page)) {
|
|
unlock_page(page);
|
|
continue;
|
|
}
|
|
|
|
if (page_has_buffers(page)) {
|
|
lastoff = page_offset(page);
|
|
bh = head = page_buffers(page);
|
|
do {
|
|
if (lastoff + bh->b_size <= startoff)
|
|
goto next;
|
|
if (buffer_uptodate(bh) ||
|
|
buffer_unwritten(bh)) {
|
|
if (whence == SEEK_DATA)
|
|
found = 1;
|
|
} else {
|
|
if (whence == SEEK_HOLE)
|
|
found = 1;
|
|
}
|
|
if (found) {
|
|
*offset = max_t(loff_t,
|
|
startoff, lastoff);
|
|
unlock_page(page);
|
|
goto out;
|
|
}
|
|
next:
|
|
lastoff += bh->b_size;
|
|
bh = bh->b_this_page;
|
|
} while (bh != head);
|
|
}
|
|
|
|
lastoff = page_offset(page) + PAGE_SIZE;
|
|
unlock_page(page);
|
|
}
|
|
|
|
/* The no. of pages is less than our desired, we are done. */
|
|
if (nr_pages < num)
|
|
break;
|
|
|
|
index = pvec.pages[i - 1]->index + 1;
|
|
pagevec_release(&pvec);
|
|
} while (index <= end);
|
|
|
|
if (whence == SEEK_HOLE && lastoff < endoff) {
|
|
found = 1;
|
|
*offset = lastoff;
|
|
}
|
|
out:
|
|
pagevec_release(&pvec);
|
|
return found;
|
|
}
|
|
|
|
/*
|
|
* ext4_seek_data() retrieves the offset for SEEK_DATA.
|
|
*/
|
|
static loff_t ext4_seek_data(struct file *file, loff_t offset, loff_t maxsize)
|
|
{
|
|
struct inode *inode = file->f_mapping->host;
|
|
struct ext4_map_blocks map;
|
|
struct extent_status es;
|
|
ext4_lblk_t start, last, end;
|
|
loff_t dataoff, isize;
|
|
int blkbits;
|
|
int ret = 0;
|
|
|
|
mutex_lock(&inode->i_mutex);
|
|
|
|
isize = i_size_read(inode);
|
|
if (offset < 0 || offset >= isize) {
|
|
mutex_unlock(&inode->i_mutex);
|
|
return -ENXIO;
|
|
}
|
|
|
|
blkbits = inode->i_sb->s_blocksize_bits;
|
|
start = offset >> blkbits;
|
|
last = start;
|
|
end = isize >> blkbits;
|
|
dataoff = offset;
|
|
|
|
do {
|
|
map.m_lblk = last;
|
|
map.m_len = end - last + 1;
|
|
ret = ext4_map_blocks(NULL, inode, &map, 0);
|
|
if (ret > 0 && !(map.m_flags & EXT4_MAP_UNWRITTEN)) {
|
|
if (last != start)
|
|
dataoff = (loff_t)last << blkbits;
|
|
break;
|
|
}
|
|
|
|
/*
|
|
* If there is a delay extent at this offset,
|
|
* it will be as a data.
|
|
*/
|
|
ext4_es_find_delayed_extent_range(inode, last, last, &es);
|
|
if (es.es_len != 0 && in_range(last, es.es_lblk, es.es_len)) {
|
|
if (last != start)
|
|
dataoff = (loff_t)last << blkbits;
|
|
break;
|
|
}
|
|
|
|
/*
|
|
* If there is a unwritten extent at this offset,
|
|
* it will be as a data or a hole according to page
|
|
* cache that has data or not.
|
|
*/
|
|
if (map.m_flags & EXT4_MAP_UNWRITTEN) {
|
|
int unwritten;
|
|
unwritten = ext4_find_unwritten_pgoff(inode, SEEK_DATA,
|
|
&map, &dataoff);
|
|
if (unwritten)
|
|
break;
|
|
}
|
|
|
|
last++;
|
|
dataoff = (loff_t)last << blkbits;
|
|
} while (last <= end);
|
|
|
|
mutex_unlock(&inode->i_mutex);
|
|
|
|
if (dataoff > isize)
|
|
return -ENXIO;
|
|
|
|
return vfs_setpos(file, dataoff, maxsize);
|
|
}
|
|
|
|
/*
|
|
* ext4_seek_hole() retrieves the offset for SEEK_HOLE.
|
|
*/
|
|
static loff_t ext4_seek_hole(struct file *file, loff_t offset, loff_t maxsize)
|
|
{
|
|
struct inode *inode = file->f_mapping->host;
|
|
struct ext4_map_blocks map;
|
|
struct extent_status es;
|
|
ext4_lblk_t start, last, end;
|
|
loff_t holeoff, isize;
|
|
int blkbits;
|
|
int ret = 0;
|
|
|
|
mutex_lock(&inode->i_mutex);
|
|
|
|
isize = i_size_read(inode);
|
|
if (offset < 0 || offset >= isize) {
|
|
mutex_unlock(&inode->i_mutex);
|
|
return -ENXIO;
|
|
}
|
|
|
|
blkbits = inode->i_sb->s_blocksize_bits;
|
|
start = offset >> blkbits;
|
|
last = start;
|
|
end = isize >> blkbits;
|
|
holeoff = offset;
|
|
|
|
do {
|
|
map.m_lblk = last;
|
|
map.m_len = end - last + 1;
|
|
ret = ext4_map_blocks(NULL, inode, &map, 0);
|
|
if (ret > 0 && !(map.m_flags & EXT4_MAP_UNWRITTEN)) {
|
|
last += ret;
|
|
holeoff = (loff_t)last << blkbits;
|
|
continue;
|
|
}
|
|
|
|
/*
|
|
* If there is a delay extent at this offset,
|
|
* we will skip this extent.
|
|
*/
|
|
ext4_es_find_delayed_extent_range(inode, last, last, &es);
|
|
if (es.es_len != 0 && in_range(last, es.es_lblk, es.es_len)) {
|
|
last = es.es_lblk + es.es_len;
|
|
holeoff = (loff_t)last << blkbits;
|
|
continue;
|
|
}
|
|
|
|
/*
|
|
* If there is a unwritten extent at this offset,
|
|
* it will be as a data or a hole according to page
|
|
* cache that has data or not.
|
|
*/
|
|
if (map.m_flags & EXT4_MAP_UNWRITTEN) {
|
|
int unwritten;
|
|
unwritten = ext4_find_unwritten_pgoff(inode, SEEK_HOLE,
|
|
&map, &holeoff);
|
|
if (!unwritten) {
|
|
last += ret;
|
|
holeoff = (loff_t)last << blkbits;
|
|
continue;
|
|
}
|
|
}
|
|
|
|
/* find a hole */
|
|
break;
|
|
} while (last <= end);
|
|
|
|
mutex_unlock(&inode->i_mutex);
|
|
|
|
if (holeoff > isize)
|
|
holeoff = isize;
|
|
|
|
return vfs_setpos(file, holeoff, maxsize);
|
|
}
|
|
|
|
/*
|
|
* ext4_llseek() handles both block-mapped and extent-mapped maxbytes values
|
|
* by calling generic_file_llseek_size() with the appropriate maxbytes
|
|
* value for each.
|
|
*/
|
|
loff_t ext4_llseek(struct file *file, loff_t offset, int whence)
|
|
{
|
|
struct inode *inode = file->f_mapping->host;
|
|
loff_t maxbytes;
|
|
|
|
if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
|
|
maxbytes = EXT4_SB(inode->i_sb)->s_bitmap_maxbytes;
|
|
else
|
|
maxbytes = inode->i_sb->s_maxbytes;
|
|
|
|
switch (whence) {
|
|
case SEEK_SET:
|
|
case SEEK_CUR:
|
|
case SEEK_END:
|
|
return generic_file_llseek_size(file, offset, whence,
|
|
maxbytes, i_size_read(inode));
|
|
case SEEK_DATA:
|
|
return ext4_seek_data(file, offset, maxbytes);
|
|
case SEEK_HOLE:
|
|
return ext4_seek_hole(file, offset, maxbytes);
|
|
}
|
|
|
|
return -EINVAL;
|
|
}
|
|
|
|
#ifdef CONFIG_EXT4CRYPT_SDP
|
|
static int ext4_check_sdp_info(struct file *file)
|
|
{
|
|
struct address_space *mapping = file->f_mapping;
|
|
struct inode *inode = mapping->host;
|
|
struct ext4_crypt_info *ci = NULL;
|
|
|
|
ci = ext4_encryption_info(inode);
|
|
if (ci && ci->ci_sdp_info)
|
|
return -ENOENT;
|
|
|
|
return 0;
|
|
}
|
|
#endif
|
|
|
|
const struct file_operations ext4_file_operations = {
|
|
.llseek = ext4_llseek,
|
|
.read_iter = generic_file_read_iter,
|
|
.write_iter = ext4_file_write_iter,
|
|
.unlocked_ioctl = ext4_ioctl,
|
|
#ifdef CONFIG_COMPAT
|
|
.compat_ioctl = ext4_compat_ioctl,
|
|
#endif
|
|
.mmap = ext4_file_mmap,
|
|
.open = ext4_file_open,
|
|
.release = ext4_release_file,
|
|
.fsync = ext4_sync_file,
|
|
.splice_read = generic_file_splice_read,
|
|
.splice_write = iter_file_splice_write,
|
|
.fallocate = ext4_fallocate,
|
|
#ifdef CONFIG_EXT4CRYPT_SDP
|
|
.check_sdp_info = ext4_check_sdp_info,
|
|
#endif
|
|
};
|
|
|
|
const struct inode_operations ext4_file_inode_operations = {
|
|
.setattr = ext4_setattr,
|
|
.getattr = ext4_getattr,
|
|
.setxattr = generic_setxattr,
|
|
.getxattr = generic_getxattr,
|
|
.listxattr = ext4_listxattr,
|
|
.removexattr = generic_removexattr,
|
|
.get_acl = ext4_get_acl,
|
|
.set_acl = ext4_set_acl,
|
|
.fiemap = ext4_fiemap,
|
|
};
|
|
|